Mac Tip #123/15-Oct-2003
Short-Term Memory

When you buy a computer it contains a certain amount of RAM, or Random Access Memory. This is short-term memory which can only remember things while power is running through it. On desktop computers such as the iMac that is when it is plugged in and switched on.

Whatever is contained in the RAM disappears as soon as you switch the machine off (which includes restarting it).

When you’re doing something on your computer you’re usually using the RAM most of the time.

Let’s say for example that you’re typing an email. You make a new message and enter an email address, a subject and then start in on the message. All of this is being stored in the computer’s RAM. If there is a power cut while you’re in the middle of this process anything you’ve typed will just disappear. There would be no hope of getting it back.

That’s where saving your work comes in. If your email software gives you the opportunity of saving drafts as you go along then you can avoid the problems of the power going off or of wiping out something you intended to keep.

When you Save a file the computer “writes” the information on to the Hard Drive. This is semi-permanent, in the way that words written in pencil on paper are semi-permanent — you can deliberately erase them later, but they’ll stay put till then.

If you save your document to disc you can turn the computer off and later retrieve that document because it was stored on the hard drive.

To help prevent losing information while you type be sure to save early and often.